Internal combustion engine of the liquid fuel injection compression ignition type



June 4, 1935. H. R. RICARDO 2,003,311

INTERNAL COMBUSTION ENGINE OF THE LIQUID FUEL INJECTION COMPRESSIONIGNITION TYPE Filed Nov. 13, 1931 2 Sheets-Sheet '1 Fig.1.

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June 4, 1935. H. R. RICARDO 2,003,311

INTERNAL COMBUSTION ENGINE OF THE LIQUID FUEL INJECTION COMPRESSIONIGNITION TYPE Filed Nov. 13, 1931 2 Sheets-Sheet 2 IN VE N TOR PatentedJune 4, 1918 5 INTERNAL ooivmusrion nnon re OF-THE noon) FUEL INJECTIONCOMPRESSION IGNITION TYPE Harry Ralph Ricardo, London, EnglandApplication. November 13, 1931, Serial No. 574,8 In Great BritainJanuary 13, 1931 7'Claims. (01. 123-32) This-invention relates tointernal combustion engines of the liquid fuel injection compressionignition type in which substantially the whole-of the charge is forcedduring the compression stroke into a pocket constituting the combustionchamber, and hasfor its object to provide an improved engine which willbe eflicient and flexible in operation.

To this end an internalcombustion engine of the above type according tothe present invention conveniently comprises a water-cooled pocketformed in the cylinder head and constituting the combustion chamberwhich forms the majorpart of the combustion space, a plug which isdisposed within the mouth of the combustion chamber pocket and so formedand arranged that it will tend to attain and be maintained at ahigh-temperature during working of the engine, a restricted passagebeing so formed in the plug that at the end of the compression strokethe charge in the combustion chamber will be caused to be in a state ofrotation as a whole, the circumferential portions of this rotating aircharge sweeping across the inner end of the passage, and a fuelinjection device adapted'to deliver a jet of fuel toward a part of thehot surface across which the. circumferential portion of the rotatingair charge sweeps as it approaches the inner end of the passage.

Conveniently, the formation of the pocket and cf the inner end of theplug is such as to provide a combustion chamber which is ofsubstantially circular-or oval cross-section in planes which areparallel both to the axis of the plug and the axis of the restrictedpassage in the plug, the passage passing either obliquely through theplug or being formed by providing a groove inthecircumferential surfaceof the plug so that theaxis of the passage is substantially tangenti'alwith respect to the part of the wall of V the combustion chamberadjacent to which its inner "end lies, 'whereby rapid rotation of thecharge tends to be set up by the entry of the air through the obliquepassage, and this rotation tends to be maintained owing to the form ofthe combustion chamber.

In any case the'fuel jet is preferably delivered toward a partof theinner surface -of the plug lying as near to the edge of the inner endofthe passage as is practicable while avoiding'the direct injection offuel into the passage. In this way the driving out-through the passageof unburnt air which may lie between the inner end of the passage andthe point at which the jet approaches the plug due to the combustion andexpansion or eliminated. In order to achieve this end it is generallydesirable to employ a type of spray-e er which will produce aconcentrated cone of spray so that the area of the plug toward which 5the spray is directed is exactly determined.

The point in the combustion chamber wall at which the fuel injectiondevice is situated may vary but conveniently it is so situated withrelation to the part of the inner surface of the plug 10 toward whichthe'jet of fuel is directed that the axis of this jet passes through oradjacent to the-axis of the combustion chamber and pref erably, but notnecessarily, obliquely with respect to the axis of the plug. 15

Ina convenient arrangement the mouth of the pocket is of cylindricalform and its inner end is domed, while the plug is externallycylindrical and is formed concave at its inner end so that the interiorof the combustion chamber is of substantially spherical or oval form,the plug fitting loosely within the mouth of the pocket'so that thetransference of heat from the plug to the cooled walls surrounding it isreduced and the plug is thusenabled-to attain and be maintained at ahigh temperature during operation of the engine. Further, by reason ofthe loose fit of the plug heat-resisting metals of low heat conductivitywhich generally have high coeflicients of expansion may be used forthe'plug while the .30 water jacket of the pocket can be carried down toand around the mouth of this pocket in which the plug lies. v

It will be appreciated thatthe present invention is not concerned withthe detailed composition of the plug and it is obvious that the metal orwhich the plug is formed may vary over a wide range. 5 In general asteel which is suitable forexhaust valves should be satisfactory for usein the plug. For. instance, any heat-resisting steel having a highpercentage of chromium combined with tungsten, nickel, or silicon togive the non-oxidiz ing properties at high temperatures is satisfactoryas regards freedom from scaling. Siliconchromium steels are not onlyhighly resistive to scaling but are free from any tendency to splitunder the most drastic conditions oi service. Furthermore, such steelsgive the required heat- [resistingproperties coupled with machinabilitybeing formed for example of circular cross-sec as indicated in Figure 2,while the cross-sectional tion at its outer end and ofother-cross-section such as substantially crescent or kidney shape atits inner end, the cross-sectional area of the inner end in either casebeing preferably approximately three-flfthsof that at its outer end. Theplug may either he wholly @over the cylinder bore or may lie partly toone side and overlap the cylinder bore and in the latter case the plugmay be, retained in place in the mouth of the pocket solely-by, reasonof its lyin Partly to one side of the cylinderbore although a retainingring may be providedflf desired, this ring serving primarily to maintainthe plug inplace inthe mouth. of the pocket during assembly ordismantling of the cylinder head.' Suchring, however, may be foundundesirable since it tends to increase the effective area of contactbetween the plug and the cooled wall surrounding it and thus to reducethe temperature attained by the plug.

- It is'a furtherobject of the invention to previde a' new and improvedmethod of eflecting combustion in an internal combustion engine of theliquid' fuel injection compression ignition The invention may he carriedinto practice in various ways but one construction accor i to thisinvention is illustrated by way of example Figure 1 is a sectional sideelevation,

Figure 2 is a section on the line 2-2 of Figure. I/and p v w Figure 3 isa similar view to Figure 1 of a modification of the inventiont v In theconstruction illustrated iri Figures 1 and 2athe engine comprisesacylinder A provided with awater-cooled cylinder head B towhich thepiston A 'within the cylinder is adapted to approach closely 'at the end'ofthe compression stroke. .Formed in the cylinder head B are inletandexhaust'ports' C and D, controlled by poppet valves C D e formed inthe cylinderhead is a water- .cooled pocket F the mouth of which is ofcylindrical form while its inner end is of domed or hemispherical form.as shown in Figure 1, the mouth of'the pocket lying-partly to one sideof and partly overlapping the cylinder bore as shown. Loosely disposedwithin the cylindrical mouth of the-pocket is an external] cylindricalplug G formed of heat-resisting ma rial of low conductivity, thegreater. part of the exterior of this plug being of somewhat, less"diameter than internal diameter of the cylindrical mouth or the pocketso that the wart: the plug is sepa-- rated from the mouth of the pocketby; air gap as indicated at 1 The plug has formed on its outercircumferential surface a dlange G which bears -a retaining ring (3screwed into the mouth of the pocket.- A set screwG- projects from thecircumferential surface or the plug and engages a slot in thecylinderhead so asto prevent rotation of the plug within the pocket. I

The inner end of the plug is formed concave was to provide a combustionchamber of substantially spherical form as shownand a passage Gpassesobliduely through theplug from the part of the outer end of theplug which overlaps the cylinder bore, to the-interior of the plug, thispassage being substantially tangential with respect to the wall-of thecombustion chamber and being gradu l reduced indiameter from itsouter'end towards its inner end; The shape of the passage when viewed'incross-section may be circular throughout its length or, for example.

socket for a fuel injection sprayer H adapted to deliver a singleconcentrated jet of fuel in such a direction that-this fuel is directedtoward the inner surface'of the plug G atapoint lying immediately to theleft of the inner end of the pasl0 sage G in-Figure 1,-the part of theinner surf face of this plug lying as near as is practicable to theinner end of the passage while avoiding direct injection-of fuel intothis passage. Also q formed inthe upper wall of the pocket is a second15 socket adapted to receive an electrical heater J of the hot wire typefor starting purposes.

The operation of the engine is as follows. During operation of theengine the plug G by reason ofthe material of which it isformed and thesmall contact which itmalges with th cooled .walls of the pocket Fattains and is maintained at a-high temperature. During the compressionstroke substantially the whole of the air ch'arge is iorced through thepassage 6}- in the plug G into the pocket, thesubstantiallytangentialentry of the charge into thepocket causing the whole 7 charge in thepocket to. be in a state of rotation at the end of the compressionstroke about an axis approximately at right angles to' the plane inwhich lie the vertical axes of the pockethnd of. the cylinder bore sothat the circumferential portiorrof the air charge as it rotates as awhole in the combustion chamber bore, sweeps across the inner end of thepassage (3*. At or about 8 the'end of the compression stroke fuel isde-. livered through the sprayer H] and this fuehis sprayed toward thepart of the inner surface of vthe plug across which the circumferentialportion' of therotating air charge sweepssubstan- 40 tially inimediatelybefore itreaches the inner end of the passage G. Thus by reason of therotation of the air charge, the.,circumferentiai portionsiof charge comeprogressively into contact with the fuel spray adjacent the plug so 46that the-fuel and air are. eillciently intermingled "and burnt. Furtherthe tendency for unburnt air tobe driven out through the passage G witha consequent loss of air available for combustion purposes is reduced oreliminated sinceany given 50 part of the mutating air chargeonly comesinto i contactgwith the fuel spray immediately before such portion oftheair charge-reaches the inner. end of the passage in the plug throughwhich the charge. during expansion ,-passes to .the'cylinder bore. Thereis thus substantially nounburnt air between the part of the air chargebeing burnt with the fuel at any moment and the point at which the burntgases leave the combustion chamber so that as the. burning gases expandthey can pass directly out of the combustion A ichamber without drivingany unburnt air before them while substantially the whole. of the-airmust come into eontact with the fuel spray beforeleaving the combustionchamber.- to

fame construction shown it will be seenthat the water-cooled jacket forthe pocket extends" down to and around themouth ofthis pocket while thesocket for the fuel sprayer passes through the wateriiacket so,that'thissprayer seating is also. effectively cooled. Further the plug itself isfree to expand and contract under temperature variations and isnotsubject to un- K formed integral therewith and disposed in and areaof contact between the plug and the cooled wall of-the' pocket and thusenable the plug to attain an evenhigher temperature, the plug being thenretained in place solely by reason of its lying partly to one side ofthe cylinder bore. In the modified construction illustrated in Figure 3vthe construction is the same as that shown in Figures 1 and 2 exceptthat the domed inner end of the'pocket is provided with a liner K whichlies adjacent to but is separated by a small air gap from the wall ofthe pocket and is conveniently formed of a heat-resisting metal of lowheat conductivity. This liner absorbs heatduring each combustion periodand thus tends to heat up the next air charge compressed into'thechamber.

This liner is conveniently supported by a boss passing through a bore inthe wall of the pocket,

this boss' being retained in place by a nut K 4 the passage is completedwhen the plug is in position by the adjacent cooled wall surrounding theplug. In this case it will be seen that the axis of the passage is stillsubstantially tangential with respect to the wall of the combustionchamber but if such a construction is employed in the arrangement showninthe drawingthe rotation of the charge within the combustion chamberwould ,be in a substantially opposite direction from that in which itrotates in Figure 1. The point on the inner wall of the plug towardwhich the fuel jet is directed would,preferably be, however,approximately the-same as in the construction shown in Figure l andwould thus lie at a point on the side of the inner end of the passageremote from the cylinder axis where the circumferential portion of therotating air charge would sweep'across it immediately before it reachedthe inner end of this passage.

Withan engine according to this invention wherein the plug attains andis maintained at a high temperature during working of the engine,burning of the fuel and air begins substantially instantaneously at thebeginning of the fuel injection period, whereby the rate of pressurerise can be controlled substantially throughout the whole fuel injectionperiod by controlling the rate -of'"'injection. Thus by suitable controlof the rate of injection smooth and flexible operation of the engine canbe obtained.

It is to be understood that the form of the combustion chamber pocketand of the plug, the position'of the fuel injection device fordelivering fuel so that it will be sprayed toward the required part ofthe plug and other constructional details may be modified withoutdeparting from this invention. v

What I claim as nrv invention and desire to secure by Letters Patentis:- V

-1. In van internaLcombustionengine of the liquid fuel injection type,the combination with acylinder, of means defining a combustion cham-.ber communicatingwith said cylinder and forming the major portion ofthe compression space at the end of the compression stroke, said meanscomprising a structure providing a pocket having a mouth and a heatretaining plug disposed within the mouth, said plug being provided witha passage therein of substantial length through which the entire volumeof burning gas flows during the working stroke from the combustionchamber into the cylinder bore and through which substantially theentire air charge is delivered and during the compression stroke causedto sweep about theinternal surfaces only of said pocket and plug, and afuel injection device delivering a jet of fuel so directed as to projectsubstantially the whole of the fuel charge toward and with suflicientvelocity to causeparticles of fuel which may be unburned to impinge ona. portion of the heated internal surface of said plug lying adjacentthe passage and swept over by the circulating charge as it approachesthe passage. a

2. In an internal combustion engine of .the liquid fuel injection type,the combination with a cylinder, of means defining a combustion chambercommunicating with said cylinder and forming the major portion of .thecompression space at the end of the. compression stroke, said meanscomprising a structure providing a cooled'pocket having a mouth and aheat resisting plug of low conductivity attaining a high temperatureduring operation of the engine and so supported in said mouth that thereis no free flow-of heat therefrom, said plug being provided with apassage therein of substantial length through which the entirevolume ofburnin ggases flows during the working stroke from the combustionchamher into the cylinder bore and through which substantially theentireair charge is delivered and caused to sweep about the internalsurfaces only of said pocket and plug during the compression stroke; anda fuel injection device delivering a jet of fuel so directed as toproject substantiallythe whole of the fuelcharge toward and withsuiiicientvelocity to cause particles of fuel which may be unburned toimpinge on a--'portion of the heated internal surface of said pluglyingadjacent the'passage and swept over by the circulating charge as itapproaches the passage.

3; In an internal combustion engine of the liquid fuel injection type,the combination with a cylinder, of means defining a combustion chambercommunicating with said 'cylinder and forming the major portion of thecompression space at the end of the compression stroke, said meanscomprising a' structure providing a pocket hav-.

ing a mouth and a heat resisting plug f low conductivity disposedlooselywithin the mouth, said pocket and mouthbeing formed to providegenerally rounded internal surfaces presenting a substantiallyclosedcurved path through which gases may be rotated, said, plug beingprovided with a passage therein directed generally tan-f gentially ofthe said curved path through. which the working stroke from thecombustion chamber into the cylinderbore and through which substantiallythe entire air charge is delivered and 65 *the entire volume of burninggas flows during In an internal combustion engine of the 775 i 2,003,311liquid fuel injection type, the combination with 6- Amel hod ofeflectins c m i n 11111 a cylinder, of means defining a combustion chamternal combustion engine of-the liquid fuel 'in ber communicating withsaid cylinder and formjection compression ignition type which coming'the major portion ofthe compression space prises thesteps; offorcingsubstantially'the'whole at the end of the compression stroke. said means.of the air. charge into the combustion chamber comprising a structureproviding a pocket having 4 during the compressio'n stroke, supplyingheat a mouth and a heat retaining plug disposed with- 'to theaircharsedurlnu P8 886 h f in the 1 t th, said pocket n i plug providingcombustion chamber; circulating the whole of --together a substantiallyuninterrupted iniemal theiair charge about the cha'mber'in' astate ofsurface of generally spherical outline, said plug undivided,uninterrupted, andorganized rotation- ;being provided with a passagetherein, of sub-. and past the point of entry .thereof into the stantialmogul leading mm said chamber in a chamber. supplying heat to thecirculatin r directiohgenerally tangential to th said inter-: charge ata point. l s ly adia n t the point nal surface through which the entirevolume of of entry of the-air charge'as the charge anburning, gas flowsduring the workingstroke from preaches the latter, delivering a-jet ofliquid fuel the combustion chamber into the cylinder bore into theaircharge'towardandin close proximity and through which substantiallythe entire air to said last named point O to form at 5 charge isdelivered and during the compression, last named points completelyinflammable mixstroke A caused to sweep about the generally ture and toinitiate combustion, whereby the spherical surface only of said pocketandplug, whole of the air chargeis caused to follow a path and a fuelinjection device delivering a jet of fuel generally directed so as tointersect the fuel jet ,so directed as to project substantially thewhole adjacent said last named point and in advance 'of the fuel chargetoward and with sufllcient ve-. only. as regards direction of movementofthe,

locity to cause particles of fuel which may be un- 'air charge, of thepoint of entry of the air charge, bumed'to impingeon a portion of theheated inand discharging the resultant mixture from the ternal surfaceof said plug lying adjacent the combustion chamber at the said point ofentry passage and swept over by the circulating charge of the air chargewithout substantial heat loss.

asit approaches the passage, 2 y; 7. A method o'f etfecting'combustlon man m 1 .5. In an internal combustion engine, of the ternalcombustion'engine of the liquid fuel inliquid fuel injection type, thecombination with jection compression ignition type whichv coma cylinder,of means defining a combustion champrises the steps of forcingspbstantiallythe whole ber communicating with said cylinder form of theair charge into thecombustion chamber ing the major'portion of thecompression, e during the compression stroke, supplying heat at the endof the compressionstroke, said cans; to the air charge during passagethereof into/the.

comprising a structure providing a pockethaving combustion chamber,circulating the whole of a mouth and a heat-retaining plug' disposedwiththe air charge about thechamber in a state of in thejnouth, theinternal surfaces of saidpocket undivided, uninterrupteiand organizedrotation .and'mouth affording a substantially smooth un-. and past thepoint 'ofentry thereof into the on a portion of the hen internalinterrupted contour, said .plug being provided! chamber. supplying heatto the circulating air with a passage therein of substantiallengthcharge at a point closely adjacent to the point through which theentire'vdlumc' of burning gas of entry of the air charge as the chargeapflows during the wor I stroke fromthe com- 'proaches thelatter',delivering a Jet of liquid fuel bustion chamber into the cylinder boreand through the rotatingair charge from a point through whichsubstantially the entire air charge remote from .said'last named pointand toward is delivered and during the compression stroke and in-clo'seproximity to said last named point caused to sweep about the internalsurfaces only only to format such last named point a comof said pocketand plug, and a fuel injection-devi ce delivering a jet of fuel sodirected as to project substantially the whole of the fuel charge towardand with suflicient velocity to cause ticles of fuel which maybeunburned to imp e stlfface of said plug lying adiacentt e e and swepcover by the circulating charge as it approaches the passage, said fuelinjection device being disposed iii-the smooth contoured portion of .the

pocket gene opposite the 'plug, whereby the outer portion of therotating air charge may Lsweep twice across the about the pocket.

fuel jet in once I 'pletely inflammable mixture and'to initiate comaircharge, and discharging the resultant mix-' ture from the combustionchamber at the said "point of entry ofthealrchargewithoutsubstantialheatloss. V .5 "I HaRRY'RAIB-HRICAWO.

follow a path generally directed so as

